anchor to element

I am using the WP Video Lightbox by to create a video pop up on a practice website. I am trying to use a cover image as a trigger. However, I cannot make shortcode link to a cover image on the page. It will only link to the external image within the media library:

This works:

[video_lightbox_youtube video_id=”vSROSencBss” width=”640″ height=”480″ anchor=”https://consultio.infy.uk/wp-content/uploads/2025/07/video-1.png”%5D
[video_lightbox_youtube video_id=”vSROSencBss” width=”640″ height=”480″ anchor=”https://youtu.be/vSROSencBss?si=g8BXAMam2LUm3tWJ”%5D

However, when I create an anchor tag for the shortcode pop up to link to, it does not work:

[video_lightbox_youtube video_id=”vSROSencBss” width=”640″ height=”480″ anchor=”videoposter”]

[video_lightbox_youtube video_id=”vSROSencBss” width=”640″ height=”480″ anchor=”https://youtu.be/vSROSencBss?si=g8BXAMam2LUm3tWJ”%5D

Can I only link to an image that is in the media library? I want to link to an image on the page. Any help would be most appreciated.

The page I need help with: [log in to see the link]